Drop knife



Oct. 21, 1941; B. w. HANLE DROP KNIFE Filed Dec. 5, 1958 1 .5. a a PM 27* INVENTOR fien h M m w W. rm .n R Q Patented Oct. 21, 1941 DROP KNIFE Benjamin William Hanle, Elizabeth, N. .T., as-

signor to Eagle Pencil Company, a corporation of Delaware Application December 5, 1938, Serial No. 243,972

2 Claims.

An object of the present invention is to provide a drop pen knife of extremely simple and inexpensive construction, devoid of any mechanism or parts apt to jam or bind, and which is yet sturdy and rugged to serve even for relatively heavy duty.

In the accompanying drawing in which is shown one of various possible embodiments of the several features of the invention:

Fig. l is a perspective View of the pen knife in closed position,

Fig. 2 is a View similar to Fig. 1 showing the knife in open position,

Fig. 3 is a view in longitudinal cross-section taken on line 3-3 of Fig. 5, and on a larger scale than Fig. 1,

Fig. 4 is a fragmentary View similar to Fig. 3, showing the blade in open position,

Fig. 5 is a view in longitudinal cross-section taken on line 55 of Fig. 3, and

Figs. 6 and 7 are views in transverse crosssection taken respectively on lines 6-45 and II of Fig. 3.

Referring now to the drawing, the knife includes a hollow handle H which may be desirably of vulcanite, Bakelite, Celluloid or other molded material, although it may be of metal if desired. Desirably, the handle of the casing comprises a flattened tube I!) with a plug II fitted and cemented into the rear end thereof, and a generally similar plug I2 similarly fitted and cemented into the front end thereof. Plug I2 has an elongated slot I3 therethrough to permit the movement of the blade B into and out of the handle.

The blade has a conventional cutting edge I4, a thicker back I5 and a shank I6, the end of which rests against the plug II when the blade is in closed position, with the point I1 of the blade accommodated within the slotted plug I2. One of the faces of the blade B is provided with a protuberance I8 which may be a rivet head, but is preferably an embossment near the base of the blade proper. That protuberance I8 abuts the shoulder I9 determined by the inner end of plug I2, and prevents the blade from escaping from the handle when it reaches open or exposed position.

Detent means is provided to retain the blade in closed position as in Fig. 3 or in open position as in Fig. 4, as the case may be. This detent comprises a finger mounted on the handle H and protruding into the interior near the forward end thereof. That finger as shown in Fig. 3 is in the path of the blade B, and thus blocks outward movement thereof. In the position shownin Fig. 4, that finger 20 extends into a notch 2| in the shaft of the blade adjacent the protuberance I8, which notch has an edge 22 perpendicular, to the back I5, so that the blade is blocked against returning to closed position from exposed or operative position.

The detent finger 20 may be released at will to permit the blade to drop from protected or from operative position, by the construction now to be described. For this purpose, the detent finger 20 is preferably an integral part of a leaf spring 23 extending longitudinally of the edge of the handle and accommodated in a longitudinal slot 24 there-through. The rear end 25 of the leaf spring 23 is preferably curved and rests in a corresponding groove 26 in-the handle wall. The spring is mounted in a non-resilient carrier 27, preferably of channelstock which straddles the main length of the spring 23 from the detent finger 20 to near the extremity 25 of the spring. The carrier bar substantially fills or closes the slot 24, and-is afiixed therein by means of a cross-pin 28 under spring 23 and through side pieces 2'! of the carrier.

The operation will be immediately apparent, but may be briefly described. The pen knife in the position shown in Figs. 1 and 3 may be carried in the pocket in the usual manner without any danger of the blade escaping, since it is retained within the hollow handle by means of the detent. For use it is merely necessary to exert pressure, say withthe forefinger upon the end 30 of the spring carrier 21, thereby to depress the latter into the finger notch 3| in the handle I-I, causing the carrier 21 to rock about its pivot 28, and to withdraw the detent finger 2!) from out of the handle. When the handle is held with the open end thereof extending generally downward, the blade will drop by gravity to the open position shown in Fig. 4, limited by the abutment of the protuberance I8 against the end IQ of plug I2. Upon release of the finger piece 38, the spring 23 will urge the detent 20 into the notch 2I which is now in registry therewith, so that the blade is securely retained in open position, the embossment I8 preventing it from moving outward, and the detent 20 preventing it from moving inward toward the casing.

The handle even though of relatively brittle molded material has nevertheless great strength against breakage in use, for in exerting cutting pressure, the back I5 of the blade reacts against the forward upper edge of the handle as shown in Fig. 4 and the rear edge of the shank against I ert pressure on the finger piece 30, thereby to withdraw detent finger 20. When the blade is held to extend in generally upward direction, it will drop by gravity into the handle, where it willbe retained by the spring returned detent finger 20, as shown in Fig. 3.

While the invention is especially applicable to Y pen knives, it will be understood that it has a wider field of application to other uses as for in1-' i stance to nail files, toothpicks, button hooks and the like. I v v. As many changes could be made in the above construction and many apparently widely different embodiments of this invention could be a made without departing from the scope of the claims, it is intended that all matter contained in the above description or'shown in the accom panying drawing shall be interpreted as illustrative and not in a limiting sense.

Having thus described my invention, what I claimas new and desire'to secure by Letters Patent is: v

1. In a drop pen knife, the combination of a hollow handle having detent means for retaining a blade alternatively in open or in closed position, said detent means comprising a leaf spring extending along a longitudinal slot in the casing, bearing at one end against the wall of the casing and having a detent finger extending into the casing at the opposite end thereof, and carrier means for said spring comprising a, channel shaped metal piece straddling the main length of said spring, and accommodated in said longitudinal slot, and a transverse pin hingedly mounting said carrier upon the handle, one end of said carrier serving as a thumb rest for overcoming the spring and releasing the detent.

2. A drop pen knife comprising a handle, in-

, eluding a hollow fiat sleeve having plugs cemented into the opposite ends thereof, one of said the slotted plug, said blade having an embossment on one face thereof blocked by the inner edge of the slotted plug for restraining further movement of the blade when it reaches open posi-. vtion, and means locking the blade alternatively in closed or in open position, said means comprising a' detent finger to protrude into the handle near'the open end thereof and through a narrow side thereof, for coacting with the forward part of the blade to retain it in protected position, said blade having a notch in the edge of 7 its shank for accommodating said detent finger when the blade is in open position, and means for manually displacing said detent to permit gravity movement of the blade to open or closed position, said means comprising a leaf spring extending longitudinally of the handle along a longitudinal slot in a narrow side of said handle, one end of said spring resting on the wall of said han-. dle, and a carrier for said spring comprising a channel-shaped metal piece straddling said spring, substantially closing said longitudinal slot and hinged at an intermediate part thereof to said handle, said carrier extending up to the detent end of said spring and exposing therebeyond the handle engaging end of saidspring, the,

end of said carrier serving as a thumb rest for overcoming said spring and releasing the detent.

BENJAMIN WILLIAM HANLE. 

